1. Field of the Invention
The present invention relates to a sheet transporting apparatus, and more particularly to a sheet transporting apparatus, for example, for use in laser beam printers, CRT printers or like printers wherein light is projected on a photosensitive sheet to form an image thereon while the sheet is being transported.
2. Description of the Prior Art
Laser beam printers have heretofore been proposed or provided wherein a photosensitive sheet being transported in a subscanning direction at an exposure station is scanned in a direction perpendicular to the subscanning direction with a laser beam modulated in accordance with an image signal to form an image on the sheet. With such printers, variations in the speed of transport of the sheet through the exposure station deviate the scanning beam relative to the sheet, impairing the quality of the image to be formed. It is therefore generally required of such printers that the sheet be transported with high precision.
U.S. Pat. No. 4,665,408 discloses a sheet transporting apparatus for transporting sheets accurately through an exposure station in the subscanning direction. To feed the sheet to transport means provided at the exposure station and adapted for precision transport, the disclosed apparatus includes a lever which is rotatable at a fixed position to push the sheet rear end and feed the sheet to the transport means, which in turn further transports the sheet through the exposure station.
With this apparatus, however, the lever, which is rotated at the fixed position, is adapted to feed sheets of a specified size only which corresponds to the distance between the lever and the transport means at the exposure station. Thus, the disclosed apparatus is usable for sheets of the specified size only.
Accordingly, the apparatus has the disadvantage of being unusable for sheets of altered size or for a strip of photosensitive material which is cut into a sheet of particular size in conformity with the size of the image to be formed.
Such a disadvantage has been encountered not only with the above-mentioned laser beam printers but also with CRT printers and like printers or further with other devices wherein sheets must be transported at a specified speed.